Agreement among Observers with Variable Experience in the Implementation of the Yokohama System for Reporting Breast Fine Needle Aspiration Biopsy Cytopathology

Background: Fine needle aspiration biopsy (FNAB) breast remains the prime investigation in distinguishing benign breast lesions from malignant ones in low socioeconomic settings. To overcome the problems of non-uniform reporting systems in breast cytology, the Yokohama system for reporting breast fine needle aspiration biopsy cytopathology (YSRB) was introduced. Aim: To assess the agreement among observers with variable experience using YSRB in a teaching institute. Materials and Methods: Retrospective study in which all breast FNABs ( n = 1003) over one year were retrieved and re-categorized according to YSRB by three observers (postgraduate resident (PG), senior resident (SR), and consultant). Cyto-histological correlation was done in cases with discordant cytological diagnoses between SR and consultant. The agreement level between observers was calculated using the Fleiss kappa score. A P value < 0.05 was considered significant. Results: The agreement between PG-SR and PG-Consultant was 0.637 and 0.641, respectively ( P < 0.001). SR and the consultant had an excellent agreement with Fleiss’ kappa score of 0.947 ( P < 0.001), having only a few discordant cases ( n = 27). Reasons for discrepancies were evaluated in 22/27 cases where histomorphology diagnoses were available. Conclusion: YSRB can be implemented with ease as a standardized reporting system for routine reporting of breast FNABs in a tertiary care teaching institute.